1. Field of the Invention
The present invention relates to methods and instruments of meniscal repair. More specifically, the present invention relates to methods and instruments for promoting healing in meniscal repair procedures by forming open channels in the meniscal periphery to increase clot formation in a meniscal tear.
2. Description of the Related Art
The menisci of the knee are two crescent shaped lamellae on the head of the tibia that receive the femoral condyles, laterally and medially, respectively. The surfaces of the menisci are smooth. The inner portion of each meniscus, known as the xe2x80x98white zone,xe2x80x99 is avascular.
Arthroscopic surgical procedures for treating meniscal pathology are becoming increasingly more common. Meniscal tears can be repaired, for example, using the devices and techniques disclosed in pending U.S. patent application Ser. No. 09/099,869, filed Jun. 19, 1998, now U.S. Pat. No. 6,056,778 the entire disclosure of which is incorporated herein by reference. Methods and instrumentation for stimulating the healing response of the menisci and reducing clinical failure are lacking in the known art.
The present invention provides methods and instrumentation for promoting the healing of avascular meniscal tears, and reducing the clinical failure rate associated with meniscal tears.
According to a preferred method of the present invention, at least one vascular channel is formed from the avascular white zone toward the vascular periphery of the meniscus by removing a cylinder of the meniscus. The channel is formed to a depth sufficient to allow blood to flow from the vascular periphery of the meniscus to the white zone. The channel has a diameter sufficient to remain open during healing of the tear.
A preferred instrument according to the present invention is a meniscal punch with a cannulated handle attached to a cannulated cutting tube. The cutting tube has a sharp distal end used to trephine a meniscal core. A depth stop prevents over-insertion of the punch. Formations on the inside of the cutting tube near the distal cutting end enhance retention of the core within the punch. Suction tubing attached to the back of the punch extracts the core by aspiration. Preferably the formed channels are at least about 1.5-2 mm in diameter, to prevent closing during healing of the repaired meniscal tissue.
The meniscal vascular punch and method of the present invention allows the creation of a bleeding environment in a meniscal tear prior to repair. Forming the open channel by inserting the punch through the tear and into the meniscal periphery increases clot formation within the tear. The core of meniscal tissue can be removed by attaching the vascular punch to suction during penetration and removal.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.